Most types of inflatable air supported buildings or enclosures are known in the prior art. Many of these inflatable buildings are made from fabric, plastic or other flexible sheet material reinforced by cables or other elongated flexible members. In many instances, the flexible material is nonextensible although some buildings may use extensible material. Many of the prior inflatable build structures derive their technology from airship design such as that used in the envelopes of blimps. Such envelopes required high strength seams tightly sealed together to prevent loss of inflation gas pressure.
The present invention, on the other hand, is intended to be far "looser" at the seam joints. The strips of envelope material are deliberately attached together at only spaced apart locations along the seams in order to provide more relative movement between the strips when subjected to violent weather conditions at any given moment. This permits the envelope to adjust to varying pressures on certain specific zones in the envelope regardless of the pressure on the other zones of the envelope. The seams of the envelope of this enclosure are sealed by hanging internal flaps held in surface to surface contact by the internal pressure on the envelope rather than by adhesive or stitches as in the conventional envelope. This distinction is uniquely inherent in the present design.
In conventional air structures, blowers maintain internal pressures which, at a given moment, are the same throughout the enclosure. However, wind pressures impinging on large enclosures may vary over different zones, due to effects of nearby trees, buildings, topographic features, etc. This invention provides for maintaining constant pressure differentials (.DELTA.p's) between local inside and outside pressures of zones throughout large enclosures, even where external storm wind loads may vary substantially over the enclosure as a whole.
Some of the closest prior art known to applicant are applicant's own U.S. Pat. Nos. 3,638,368 and 3,762,108 issued to R. M. Pierson which show cable reinforced inflatable buildings which may be constructed with internal tethering to enable the buildings to cover large areas while maintaining a certain proximity to the ground to withstand high winds.
The present invention differs from applicant's above prior patents in that it is designed for less expensive totally on site assembly and to have a different type of seal for the connections between strips of the flexible sheet material of the envelope.